JP2012181065A - Radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation detector capable of identifying a position which radiation has entered.SOLUTION: The radiation detector comprises: a converter for reacting with neutrons to generate charged particles; a plurality of detection circuits detecting the charged particles formed on a semiconductor substrate; and a shield part for restricting an arrival direction of the charged particles that are incident to the respective detection circuits. And further, the respective detection circuits include PN junctions.

Description

  The present invention relates to a radiation detection apparatus that detects radiation.

  Some radiation detection devices that detect radiation indirectly detect radiation by acting the radiation with another substance (also referred to as a converter). The radiation includes alpha rays, beta rays, gamma rays, X rays, neutron rays, charged particle rays and the like.

Some radiation detection devices that detect thermal neutrons use boron 10 ( ¹⁰ B) in a converter. Boron 10 reacts with neutrons to generate helium 4 ( ⁴ He, α rays) and lithium 7 ( ⁷ Li). The radiation detection device detects neutrons by detecting α rays and lithium 7.

  Some radiation detection devices that detect fast neutrons use a scintillator or the like. A scintillator reacts with fast neutrons by a scintillation phenomenon to convert radiation into light. The radiation detection device detects fast neutrons by detecting the converted light. The energy of fast neutrons is generally 100 keV or higher. The energy of fast neutrons is greater than that of thermal neutrons.

JP 2002-270887 A Japanese Patent Laid-Open No. 63-40892 JP 2009-212162 A JP 63-114177 A JP-A-7-176777

  In the radiation detection device that detects thermal neutrons, particles converted by the converter fly in all directions. Therefore, it is difficult to specify the arrival direction of the particles detected by the detector. Therefore, it is difficult for the radiation detection apparatus to specify the position where the neutron is incident.

  In addition, in the radiation detection apparatus that detects fast neutrons, the light converted by the scintillator spreads in various directions, so it is difficult to specify the light arrival direction. Therefore, it is difficult for the radiation detection apparatus to specify the position where the neutron is incident.

  This invention makes it a subject to provide the radiation detection apparatus which can pinpoint the position where the radiation was incident.

  The disclosed radiation detection apparatus employs the following means in order to solve the above problems.

That is, the first aspect is
A converter that reacts with neutrons to generate charged particles;
A plurality of detection circuits for detecting the charged particles formed on the semiconductor substrate;
A shielding unit for restricting the arrival direction of the charged particles incident on each of the detection circuits;
It is a radiation detection apparatus provided with.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation detection apparatus which can pinpoint the position where the radiation was incident can be provided.

FIG. 1 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an example of a detection unit viewed from the upper surface direction of the radiation detection apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of the detection unit. FIG. 4 is a diagram illustrating a configuration example (1) of the output circuit of the detection unit. FIG. 5 is a diagram showing an example of a perspective view of the shape of the shielding metal. FIG. 6 is a diagram illustrating an example of a cross section of a radiation detection apparatus according to a modification. FIG. 7 is a diagram illustrating an example of the detection unit viewed from the top surface direction of the radiation detection apparatus according to the modification. FIG. 8 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the second embodiment. FIG. 9 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the third embodiment. FIG. 10 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the fourth embodiment. FIG. 11 is a diagram illustrating an example of sensitivity of the first converter layer and the second converter layer. FIG. 12 is a diagram illustrating an example (2) of the output circuit of one detection unit. FIG. 13 is a diagram illustrating an example (3) of the output circuit of one detection unit. FIG. 14 is a diagram illustrating a specific example of the output circuit of the detection unit in FIG. 12 or FIG.

  Hereinafter, embodiments will be described with reference to the drawings. The configuration of the embodiment is an exemplification, and is not limited to the configuration of the disclosed embodiment.

Embodiment 1
(Configuration example)
FIG. 1 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the present embodiment. The radiation detection apparatus 100 includes a P (N) type substrate 102, a silicon oxide film (SiO ₂ film) 108, a metal (shielding metal) 110, a converter layer 112, and a detection unit 120. The detection unit 120 includes an N (P) type semiconductor 121, an N (P) type semiconductor 122, a silicon oxide film 123, and polysilicon 124. The radiation detection apparatus 100 includes a wiring 131, a wiring 132, and a wiring 133. The N (P) type semiconductor 121 and the N (P) type semiconductor 122 are semiconductors containing a larger proportion of impurities than the P (N) type substrate 102. The converter layer 112 side is the upper side, and the P (N) type substrate 102 side is the lower side. The P (N) type substrate 102, the N (P) type semiconductor 121, and the N (P) type semiconductor 122 are the P type substrate 102, the N type semiconductor 121, and the N type semiconductor 122, or the N type substrate 102. , P-type semiconductor 121, and P-type semiconductor 122. The N (P) type semiconductors 121 in FIG. The N (P) type semiconductor 122 is connected to the N (P) type semiconductor 122 (not shown) in the depth direction by the wiring 132. Each polysilicon 124 is connected by a wiring 133. For the wiring, metal wiring is used. By using metal wiring, high-speed reading can be performed. As the wiring, a wiring made of polysilicon or a wiring made of an N (P) type semiconductor in the substrate may be used. A layer including the P (N) type substrate 102, the detection unit 120, and each wiring is also referred to as a circuit layer.

  A plurality of detection units 120 are formed on the P (N) type substrate 102. Each detection unit 120 may be separated from other detection units 120 by an element isolation film. The element isolation film prevents a signal detected by the detection unit 120 from affecting other detection units 120. If the signal detected by the detection unit 120 does not affect the other detection units 120, the element isolation film may not exist. The P (N) type substrate 102 is, for example, a silicon substrate. A low resistance silicon substrate may be used as the P (N) type substrate 102. The detection unit 120 is arranged two-dimensionally with a predetermined period.

  The detection unit 120 includes an N (P) type semiconductor 121, an N (P) type semiconductor 122, a silicon oxide film 123, and polysilicon 124. The N (P) type semiconductor 121 and the N (P) type semiconductor 122 are formed by ion implantation into the P (N) type substrate 102. The silicon oxide film 123 and the polysilicon 124 are formed by being formed on the P (N) type substrate 102.

The detection unit 120 detects charged particles that are α rays or Li particle rays. The detection unit 120 has a PN bond. The PN coupling may be a low capacity PN junction. By using the low-capacity PN junction, for example, the resistance in the depletion layer and the time constant in the stray capacitance are reduced, and high-speed reading is possible. Charged particles such as α rays and Li particle rays are detected by a depletion layer formed in the detection unit 120 at the time of reverse bias of the PN junction. Alpha rays or Li particle rays generate electron-hole pairs in the depletion layer near the PN junction. The depletion layer can also be formed by, for example, a MOS (Metal Oxide Semiconductor) capacitor structure. That is, the depletion layer is MOS
In the capacitor structure, it can be formed directly under the gate oxide film. The detection unit 120 detects α-rays or Li particle beams by detecting the current due to the electron-hole pairs. The PN junction may be, for example, a PN junction including a transistor drain region, a PN junction, and an epitaxial layer. The installation interval of the detection unit 120 is the position resolution of the radiation detection apparatus 100. However, when the converter layer 112 is thick, the position resolution of the radiation detection apparatus 100 also depends on the thickness of the converter layer 112. The radiation detection apparatus 100 can include an amplification circuit that amplifies a minute signal detected by the detection unit 120.

  FIG. 2 is a diagram illustrating an example of the detection unit viewed from the upper surface direction of the radiation detection apparatus. In the example of FIG. 2, the number of detection units 120 is twelve, but the number of detection units 120 is not limited to twelve. In the example of FIG. 2, an N-type semiconductor 121, an N-type semiconductor 122, polysilicon 124, and each wiring are shown. In the example of FIG. 2, the radiation detection apparatus 100 includes a transistor 141, a transistor 142, a vertical switch 151, a horizontal switch 152, and an amplifier 160. The N-type semiconductor 121, the N-type semiconductor 122, and the polysilicon 124 are periodically arranged in the vertical direction and the horizontal direction in FIG. The wiring 131 connects the N-type semiconductors 121 for each column. The wiring 132 connects each N-type semiconductor 122 for each column in a direction different from the direction of the wiring 131. The wiring 133 connects each polysilicon 124.

  Each column of the wiring 131 is connected to one transistor 141. Each transistor 141 is connected to a power source and a vertical switch 151. The vertical switch 151 turns on one of the transistors 141 as a switch. As a result, a voltage is applied to the N-type semiconductor 121 via the wiring 131 connected to the turned-on transistor 141.

  Each column of the wiring 132 is connected to one transistor 142. Each transistor 142 is connected to a power supply and lateral switch 152. The lateral switch 152 turns on one of the transistors 142 as a switch. As a result, the N-type semiconductor 122 is connected to the amplifier 160 via the wiring 132 connected to the turned-on transistor 142.

  The wiring 133 supplies a predetermined power supply voltage to each polysilicon 124. A depletion layer is formed on the P-type substrate 102 in the vicinity of the polysilicon 124 by the power supply voltage supplied to the polysilicon 124. That is, a depletion layer is formed immediately below the silicon oxide film 123. By controlling the power supply voltage, the size of the depletion layer can be controlled.

  The transistor 141 is controlled by the vertical switch 151 and becomes conductive when turned on by the vertical switch 151. Transistor 142 is controlled by lateral switch 152 and conducts when turned on by longitudinal switch 151.

  The vertical switch 151 controls the connected transistor 141 to control conduction between the power supply and the N-type semiconductor 121. The lateral switch 152 controls the transistor 142 connected to control conduction between the N-type semiconductor 121 and the amplifier 160.

  The N-type semiconductor 121, the N-type semiconductor 122, and the polysilicon 124 correspond to the source, drain, and gate of the MOS transistor, respectively.

  The voltage applied to the N-type semiconductor 121 and the polysilicon 124 may be the same.

The configuration of the detection unit 120 is not limited to the example in FIG. 2. For example, each detection unit 120 has a capacitor and accumulates charges due to electron-hole pairs as in a DRAM (Dynamic Random Access Memory). May be. In addition, the configuration of the detection unit 120 may be such that each detection unit 120 has an amplifier like a CMOS (Complementary Metal Oxide Semiconductor) sensor.
The configuration for reading current from the detection unit 120 may be the same as the configuration of the DRAM or the configuration of the CMOS sensor. The configuration of reading current from the detection unit 120 is not limited to these.

  When the P-type semiconductor 121 or the like is used, the positive and negative directions of the power supply are reversed in FIG.

  FIG. 3 is a diagram illustrating a configuration example of the detection unit. When a positive voltage is applied to the electrode polysilicon 124, the holes in the P-type substrate 102 are separated from the polysilicon 124. A depletion layer is formed in the vicinity of the polysilicon 124 of the P-type substrate 102. At this time, when charged particles (α rays or Li particle beams) are incident on the depletion layer, the charged particles generate electron-hole pairs in the depletion layer.

  When electron-hole pairs (carriers) are generated in the depletion layer, a current flows between the N-type semiconductor 121 and the N-type semiconductor 122 due to a potential difference between the N-type semiconductor 121 and the N-type semiconductor 122. By detecting this current, the incidence of charged particles can be detected. When electron-hole pairs (carriers) are generated in the depletion layer, the electron-hole pairs decay with a time constant due to the resistance and stray capacitance of the depletion layer. By generating a potential difference between the N-type semiconductor 121 and the N-type semiconductor 122 before the electron-hole pair disappears, the detection unit 120 can detect the incidence of charged particles. The size of the depletion layer can be controlled by the voltage applied to the polysilicon 124. By controlling the size of the depletion layer, the detection sensitivity of charged particles can be adjusted. That is, by increasing the depletion layer, more electron-hole pairs are generated by the charged particles, so that the detection unit 120 can easily detect the charged particles.

FIG. 4 is a diagram illustrating an example (1) of the output circuit of one detection unit. The diode of FIG. 4 corresponds to, for example, a detection portion by a PN junction of the detection unit 120 and a depletion layer immediately below the gate oxide film (hereinafter, a detection portion having a depletion layer is referred to as a diode). The diode is reverse biased. This reverse bias may be commonly applied to the PN junctions of all the detection units 120. The resistor is, for example, a resistor (high resistance) using a triode region of a MOS transistor, or a resistor (high resistance) manufactured by diffusion, polysilicon, or the like. When charged particles enter the detection unit 120, a current flows through the diode. Electric charges due to this current are output via a capacitor. This capacitor may not be present.

  FIG. 12 is a diagram illustrating an example (2) of the output circuit of one detection unit. The diodes and resistors in FIG. 12 are the same as the diodes and resistors in FIG. The amplifier in FIG. 12 is, for example, a MOS transistor. The diode is reverse biased. This reverse bias may be commonly applied to the PN junctions of all the detection units 120. When charged particles enter the detection unit 120, a current flows through the diode, and the charge due to this current is converted into a voltage by the capacitance of the detector, amplified by an amplifier, and output.

  FIG. 13 is a diagram illustrating an example (3) of the output circuit of one detection unit. The diode of FIG. 13 is the same as the diode of FIG. The switch in FIG. 13 is formed by, for example, a MOS transistor. The amplifier of FIG. 13 is similar to the amplifier of FIG. The diode is reverse biased. This reverse bias may be commonly applied to the PN junctions of all the detection units 120. When charged particles enter the detector 120 when the switch is off, a current flows through the diode, and the electric charge due to this current is converted into a voltage by the capacitance of the detector, amplified by an amplifier, and output.

  The output of the output circuit as shown in FIGS. 4, 12, and 13 can be counted by being connected to an amplifier circuit or a counting circuit, for example. Further, the depletion layer in the vicinity of the PN junction can be the capacitor. That is, the charge stored in the depletion layer can be output as a signal. The signal is read for each detection unit 120, for example, with a configuration similar to that of the DRAM. In this case, for example, by providing the reading transistor below the shielding metal 110, the influence of an erroneous signal due to the influence of charged particles can be reduced.

  FIG. 14 is a diagram illustrating a specific example of the output circuit of the detection unit in FIG. 12 or FIG. The circuit of FIG. 14 includes four MOS transistors (A, B, C, and D). In the output circuit as shown in FIG. 12, the MOS transistor A functions as a resistor, the MOS transistor B functions as a diode, and the MOS transistors C and D function as amplifiers. Terminal (a) is connected to MOS transistor A. Here, by adjusting the voltage of the terminal (a), the MOS transistor A can function as a resistor (high resistance). In the output circuit as shown in FIG. 13, the MOS transistor A functions as a switch, the MOS transistor B functions as a diode, and the MOS transistors C and D function as amplifiers. Here, by adjusting the voltage of the terminal (a), the MOS transistor A can function as a switch.

  The output circuit of the detection unit is not limited to the examples of FIG. 4, FIG. 12, FIG. 13, FIG.

  A silicon oxide film 108 is formed on each detection unit 120. The thickness (height) of the silicon oxide film 108 is, for example, 4 to 7 μm.

A converter layer 112 is formed on the silicon oxide film 108. Converter layer 112 includes boron 10 ( ¹⁰ B). Converter layer 112 may be made of only boron 10 ( ¹⁰ B). Neutrons (thermal neutrons) incident on the converter layer 112 undergo a nuclear reaction with boron 10 ( ¹⁰ B) to generate α rays and Li particle beams. At this time, the α ray and the Li particle beam each have an energy of about 1 MeV. The generated α ray and Li particle beam are emitted in directions almost opposite to each other. Accordingly, one of α rays and Li particle rays is incident on the silicon oxide film 108 side. The range of 1.5 MeV α rays in boron 10 is 4 μm. The range of the 900 keV Li particle beam in the boron 10 is 2 μm. The thickness of the converter layer 112 and the silicon oxide film 108 is set to such a thickness that the α ray or the Li particle beam reaches the detection unit 120. Moreover, when the thickness of the converter layer 112 is small, the rate at which neutrons are converted into α rays and Li particle rays decreases. The thickness (height) of the converter layer is, for example, 1 to 5 μm. Here, the converter layer 112 includes boron 10, but a substance other than boron 10 such as LiF or ZnS that converts thermal neutrons to light may be used as a substance that converts neutrons into other substances. Good.

  Further, a shielding metal 110 is formed in a portion other than the upper portion of the polysilicon 124. That is, when viewed from the upper surface side of the radiation detection apparatus 100, the shielding metal 110 is formed so as to surround the polysilicon 124 (detection unit 120).

  FIG. 5 is a diagram showing an example of a perspective view of the shape of the shielding metal. The entire shielding metal 110 in FIG. 5 is a rectangular parallelepiped, and has a shape in which a groove is formed in the portion of the detection unit 120. With this shape, charged particles incident from directly above the groove enter the detection unit 120, and charged particles incident from an oblique direction hit the shielding metal 110 and do not reach the detection unit 120. In the example of FIG. 5, the shape (in cross section) of the groove of the shielding metal is a square, but is not limited to a square, and may be another shape such as a rectangle or a circle. However, the shape (in cross section) of the groove of the shielding metal is preferably the same shape as the shape of the detection unit 120. The shape of the shielding metal 110 is not limited to the example of FIG.

  As the shielding metal 110, for example, aluminum, copper, silver, tungsten, or the like can be used. The shielding metal 110 has such a width that it does not allow α rays and Li particle beams to pass from one silicon oxide film 108 to the adjacent silicon oxide film 108. The width of the shielding metal 110 is, for example, 5 μm for aluminum, 3 μm for copper, 3 μm for silver, and 2 μm for tungsten. The width of the shielding metal 110 is desirably smaller in consideration of the detection efficiency of neutrons. This is because α rays hitting the shielding metal 110 are not detected by the detection unit 120.

  A semiconductor device including the P (N) type substrate 102, the silicon oxide film 108, the shielding metal 110, the converter layer 112, the detection unit 120, the wiring 131, the wiring 132, and the wiring 133 can be manufactured by a normal semiconductor process. The semiconductor device can be manufactured as follows.

  A silicon oxide film layer is formed on the surface of a silicon wafer (single crystal substrate) to which a P (N) type impurity is added by, for example, a thermal oxidation method. Next, a photoresist film is formed on the silicon oxide film layer. Then, the resist patterns of the N (P) type semiconductor 121 and the N (P) type semiconductor 122 are transferred by photolithography or the like, and N (P) type impurity ions are implanted to form an N (P) type semiconductor. . After removing the resist pattern, a silicon oxide film layer is formed on the entire surface.

Further, an electrode film layer is formed on the entire surface. The electrode film is formed by, for example, CVD (Chemical
A Vapor Deposition (chemical vapor deposition) method, an ALD (Atomic Layer Deposition) method or a PVD (Physical Vapor Deposition) method may be used. The electrode film layer is, for example, polysilicon.

  Next, a resist pattern for forming electrodes is transferred to the N (P) type semiconductor 121 and the N (P) type semiconductor 122 by photolithography or the like, and the silicon oxide film layer and the electrode film layer are removed. Thereby, the polysilicon 124 can be formed. For the polysilicon 124 as an electrode, a TiAlN film, a TaN film, a TaC film, a TaCN film, or the like may be used instead of the polysilicon film. Further, a metal material is stacked by sputtering or the like to form an electrode, a wiring layer, or the like. In addition, a metal layer serving as an electrode is formed under the P (N) type substrate 102.

  Next, the resist pattern is transferred by photolithography or the like, unnecessary metal is removed, and electrodes, wirings, and the like of the N (P) type semiconductor 121 are formed. The wiring can be taken out from the periphery of the semiconductor device. After removing the resist pattern, a silicon oxide film is further formed on the entire surface.

  Next, a resist pattern for forming the shielding metal 110 is transferred by photolithography or the like, and a portion that becomes the shielding metal 110 is etched to remove the silicon oxide film. A predetermined metal material is laminated on the portion from which the silicon oxide film has been removed. Thereby, the shielding metal 110 is formed. The shielding metal 110 may be formed by connecting a plurality of vias without gaps.

Next, a resist pattern for forming the converter layer 112 is transferred by photolithography or the like. That is, the shielding metal portion is masked and the silicon oxide film portion is etched. The silicon oxide film is removed and a converter layer 112 is formed in the portion. The converter layer 112, a method of introducing boron 10 ⁽¹⁰ B) simultaneously deposited and by a CVD method, a boron 10 ⁽¹⁰ B) after deposition and a method of ion implantation, boron 10 ⁽¹⁰ to the converter layer 112 B) can be included.

  In this manner, a semiconductor device including the P (N) type substrate 102, the silicon oxide film 108, the shielding metal 110, the converter layer 112, the detection unit 120, the wiring 131, the wiring 132, and the wiring 133 can be manufactured.

(Operation example)
An operation of neutron detection in the radiation detection apparatus 100 will be described. When neutrons are incident from the converter layer 112 side of the radiation detection apparatus 100, the neutrons undergo a nuclear reaction ( ¹⁰ B (n, α) ⁷ Li reaction) with the boron 10 of the converter layer 112 to form α rays and Li particle beams. Converted. One of α rays and Li particle rays is emitted to the silicon oxide film 108 side. This emitted direction is almost the same as the direction of neutron motion.

  The charged particle beam emitted toward the silicon oxide film 108 penetrates the silicon oxide film 108, the polysilicon 124, and the silicon oxide film 123 and enters the depletion layer of the detection unit 120. The depletion layer of the detection unit 120 is formed by a reverse bias potential applied from an electrode (corresponding to a gate electrode) connected to the polysilicon 124. When charged particles are incident on the depletion layer of the detection unit 120, the charged particles generate electron-hole pairs. The electron-hole pair (charge) generated in the depletion layer of the detection unit 120 is held by the capacitance of the depletion layer. The charge held in the depletion layer is detected by an electrode (corresponding to a drain electrode) connected to the N (P) type semiconductor 122. The detection unit 120 detects charged particles (α rays or Li particle rays) by detecting the charge held in the depletion layer.

  When charged particles hit the shielding metal 110, the detection unit 120 does not detect them. This is because the charged particles are attenuated by the shielding metal 110 and do not reach the detection unit 120. The arrival direction of neutrons (charged particles) detected by the detection unit 120 is limited by the shielding metal 110.

Also, the difference in angle between the direction of neutron motion and the direction of motion of charged particles emitted to the silicon oxide film 108 side is about 10 degrees at the maximum. Therefore, when charged particles are detected by a certain detection unit 120, it is considered that neutrons are incident almost directly above the detection unit 120. Therefore, the radiation detection apparatus 100 can recognize at which position the neutron is incident depending on which detection unit 120 has detected the charged particle. That is, the radiation detection apparatus 100 can determine that neutrons are incident almost directly above the detection unit 120 that has detected the charged particles. Further, the radiation detection apparatus 100 can determine the position where the neutron is incident with the position resolution of the installation interval of the detection unit 120.

  Here, detection of charged particles by the radiation detection apparatus 100 will be described with reference to FIG. When neutrons (thermal neutrons) are incident on the radiation detection apparatus 100, the converter layer 112 converts them into charged particles. Each detection unit 120 includes an N-type semiconductor 121 as a transistor source, an N-type semiconductor 122 as a transistor drain, and each polysilicon 124 as a transistor gate.

  A predetermined voltage is applied to each polysilicon 124 as a transistor gate by a power source. A depletion layer is formed on the P-type substrate 102 in the vicinity of each polysilicon 124 by the voltage.

  The radiation detection apparatus 100 can extract a signal by applying a voltage to an arbitrary detection unit 120 using the vertical switch 151 and the horizontal switch 152. Here, for example, it is assumed that charged particles are incident on the depletion layer of the detection unit 120 (upper left in FIG. 2) including the polysilicon 124A. When charged particles enter the depletion layer, electron-hole pairs are generated. When taking out the signal from the detection unit 122, the vertical switch 151 turns on the transistor 141A, and the horizontal switch 152 turns on the transistor 142A. At this time, an electron-hole pair is transferred between the N-type semiconductor 121A and the N-type semiconductor 122A due to a potential difference between the N-type semiconductor 121A serving as the source of the transistor and the N-type semiconductor 122A serving as the drain of the transistor. And current flows. By detecting this current through the amplifier 160, the incidence of charged particles in the detection unit 122 can be detected. Of course, the same applies to the other detection units 120. That is, by appropriately switching the vertical switch 151 and the horizontal switch 152, the radiation detection apparatus 100 can detect the current due to electron-hole pairs (carriers) generated in all the detectors 120. In addition, the radiation detection apparatus 100 can recognize which detection unit 120 generates a current due to electron-hole pairs (carriers) based on the state of the vertical switch 151 and the horizontal switch 152. That is, the radiation detection apparatus 100 can recognize which detection unit 120 the charged particle has entered. That is, the radiation detection apparatus 100 can determine the position above the position of the detection unit 120 where the charged particles are incident as the position where the neutron is incident. In addition, the radiation detection apparatus 100 can detect current from an arbitrary detection unit 120 by using the vertical direction switch 151 and the horizontal direction switch 152. The radiation detection apparatus 100 may include a correspondence table that stores correspondences between the states of the vertical direction switch 151 and the horizontal direction switch 152 and the position (coordinates) of the detection unit 120. The radiation detection apparatus 100 can determine the position where the neutron is incident from the correspondence table. For example, the radiation detection apparatus 100 can set the position of the center of the polysilicon 124 as the position of the detection unit 120.

(Modification)
Next, a modified example will be described. This modification has common points with the above configuration. Accordingly, here, mainly the differences will be described, and description of common points will be omitted. Here, an example in which the N (P) type semiconductor 121 is omitted is shown.

  FIG. 6 is a diagram illustrating an example of a cross section of a radiation detection apparatus according to a modification. In the radiation detection apparatus 1100 according to the modification, the detection unit 120 includes an N (P) type semiconductor 122, a silicon oxide film 123, and polysilicon 124. The N (P) type semiconductor 122 in FIG. 6 is connected to the N (P) type semiconductor 122 (not shown) by the wiring 132, respectively. Each polysilicon 124 is connected to polysilicon 124 (not shown) in the depth direction by wiring 133.

FIG. 7 is a diagram illustrating an example of the detection unit viewed from the top surface direction of the radiation detection apparatus according to the modification. FIG.
In this example, the number of detection units 120 is twelve, but the number of detection units 120 is not limited to twelve. In the example of FIG. 7, the N-type semiconductor 122, the polysilicon 124, and each wiring are shown. In the example of FIG. 7, the radiation detection apparatus 1100 includes a transistor 171, a transistor 172, a vertical switch 181, a horizontal switch 182, and an amplifier 160. The N-type semiconductor 122 and the polysilicon 124 are periodically arranged in the vertical direction and the horizontal direction in FIG. The wiring 132 connects the N-type semiconductors 122 for each column. The wiring 133 connects each polysilicon 124 in a direction different from the direction of the wiring 132. When the P-type semiconductor 122 or the like is used, the positive and negative directions of the power supply are reversed in FIG.

  Each column of the wiring 132 is connected to one transistor 171. Each transistor 171 is connected to a power source and a vertical switch 181. The vertical switch 181 turns on one of the transistors 142 as a switch. Thereby, the N-type semiconductor 122 is connected to the amplifier 160 via the wiring 132 connected to the transistor 171 that is turned on.

  Each column of the wiring 133 is connected to one transistor 172. Each transistor 172 is connected to a power source and a lateral switch 182. The lateral switch 182 turns on one of the transistors 172 as a switch. A predetermined power supply voltage is supplied to each polysilicon 124 in the column in which the switch is turned on. A depletion layer is formed on the P-type substrate 102 in the vicinity of the polysilicon 124 by the power supply voltage supplied to the polysilicon 124. By controlling the power supply voltage, the size of the depletion layer can be controlled. By controlling the size of the depletion layer, the detection sensitivity of charged particles can be adjusted. That is, by increasing the depletion layer, more electron-hole pairs are generated by the charged particles, so that the detection unit 120 can easily detect the charged particles.

  The detection of charged particles by the radiation detection apparatus 1100 will be described. When neutrons (thermal neutrons) are incident on the radiation detection apparatus 1100, they are converted into charged particles by the converter layer 112.

  A predetermined voltage is applied to each polysilicon 124 by the power supply for each column at predetermined time intervals by the operation of the lateral switch 182. A depletion layer is formed on the P-type substrate 102 in the vicinity of each polysilicon 124 by the voltage.

  Here, for example, it is assumed that the transistor 172A is turned on by the lateral switch 182. At this time, it is assumed that charged particles are incident on the depletion layer of the detection unit 122 (upper left in FIG. 7) including the polysilicon 124A. When charged particles enter the depletion layer, electron-hole pairs are generated. In the vertical switch 181, when the transistor 171 A is turned on, a current flows using an electron-hole pair as a carrier due to a potential difference between the polysilicon 124 A and the N-type semiconductor 122 A serving as the drain of the transistor. By detecting this current through the amplifier 160, the incidence of charged particles in the detection unit 120 can be detected. The same applies to the other detection units 120. When a voltage is applied to the polysilicon 124 by the lateral switch 182, a large depletion layer is generated. When charged particles enter the depletion layer, electron-hole pairs (carriers) are generated. When the detection unit 120 where the carrier is generated and the amplifier 160 are electrically connected by the vertical switch, the current by the carrier is detected. The detection unit 120 (polysilicon 124) to which a voltage is applied is switched by the horizontal switch 152. The radiation detection apparatus 1100 can detect the current (signal) from each detection unit 120 by appropriately switching the vertical switch 181 at a cycle faster than the switching cycle by the horizontal switch 182, for example. The radiation detection apparatus 1100 can recognize which detection unit 120 is a signal due to electron-hole pairs (carriers) generated by the state of the vertical switch 181 and the horizontal switch 182.

  The radiation detection apparatus 1100 has a simple configuration as compared with the radiation detection apparatus 100.

(Effect of Embodiment 1)
The converter layer 112 of the radiation detection apparatus 100 converts incident neutrons into charged particles such as α-rays and Li-particles when they react with the boron 10. The charged particles are incident on the detection unit 120 via the silicon oxide film 108. The charged particles generate electron-hole pairs in the depletion layer near the PN junction of the detection unit 120. The detection unit 120 detects charged particles by detecting a current due to the electron-hole pairs. The charged particles incident on the detection unit 120 are charged particles caused by neutrons that are incident from substantially directly above the detection unit 120. Charged particles from directions other than the direction directly above the detection unit 120 are shielded by the shielding metal 110. Therefore, charged particles do not enter the detection unit 120 from directions other than the direction directly above the detection unit 120. The position immediately above the detection unit 120 that has detected the charged particles is the position where the neutron is incident. That is, since the direction of the charged particle incident on the detection unit 120 is specified by the shielding metal 110, the position of the detection unit 120 that detects the charged particle corresponds to the incident position of the neutron. Therefore, the resolution of the position where the neutron is incident in the radiation detection apparatus 100 is the installation interval of the detection unit 120.

  The radiation detection apparatus 100 can adjust the size of the depletion layer by controlling the gate voltage (voltage applied to the polysilicon 124). The detection sensitivity of the detection unit 120 depends on the size of the depletion layer. Therefore, the radiation detection apparatus 100 can adjust the detection sensitivity of the detection unit 120 by controlling the gate voltage (voltage applied to the polysilicon 124).

  Further, since the mobility of electron-hole pairs in silicon is fast and the depletion layer of the detection unit 120 is narrow, the time constant of signal extinction is 1 ns or less. Therefore, the radiation detection apparatus 100 can read out detection of charged particles at high speed, and can shorten the dead time of the detection unit 120.

  Furthermore, radiation detection with high positional resolution can be performed in a large area by laying a large number of radiation detection apparatuses 100 on a two-dimensional plane.

  The same applies to the radiation detection apparatus 1100 according to the modification.

[Embodiment 2]
Next, Embodiment 2 will be described. The second embodiment has common points with the first embodiment. Accordingly, here, mainly the differences will be described, and description of common points will be omitted. In the second embodiment, the silicon oxide film 208 of the first embodiment is also a converter layer.

(Configuration example)
FIG. 8 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the present embodiment. The radiation detection apparatus 200 includes a P (N) type substrate 202, a metal (shielding metal) 210, a converter layer 212, and a detection unit 220. The detection unit 220 includes an N (P) type semiconductor 221, an N (P) type semiconductor 222, a silicon oxide film 223, and polysilicon 224. The radiation detection apparatus 200 includes a wiring 231, a wiring 232, and a wiring 233.

The silicon substrate 202, the metal (shielding metal) 210, the converter layer 212, and the detection unit 220 are the same as the silicon substrate 102, the metal (shielding metal) 210, the converter layer 212, and the detection unit 220 of the first embodiment, respectively. The N (P) type semiconductor 221, the N (P) type semiconductor 222, the silicon oxide film 223, and the polysilicon 224 are the N (P) type semiconductor 121, N (P) type semiconductor 122, and silicon oxide film 123 of the first embodiment. The same as the polysilicon 124. The wiring 231, the wiring 232, and the wiring 233 are the wiring 131, the wiring 132, and the wiring 1 of the first embodiment.
33.

  In the second embodiment, the silicon oxide film 108 in the first embodiment is used as the converter layer 212. By using the silicon oxide film 108 as the converter layer 212, neutrons can be converted into charged particles (α rays or Li particle rays) also in this portion. The converter layer 212 can be formed by, for example, scraping a silicon oxide film as in the first embodiment by a post process and embedding boron 10. Further, since the silicon oxide film is not present, attenuation of charged particles can be suppressed. The shielding metal 210 is formed in the same manner as the shielding metal 110 of the first embodiment.

  The height (thickness) of the shielding metal 210 is, for example, 2 μm or more. This is because, when the height of the shielding metal is small, the amount of charged particles incident on the detection unit 220 is increased and the position resolution is lowered. Further, the height (thickness) of the converter layer 212 is, for example, 2 to 4 μm. Α rays and Li particle rays generated by a nuclear reaction between neutrons (thermal neutrons) and boron 10 each have an energy of about 1 MeV. The range of 1.5 MeV α rays in boron 10 is 4 μm. The range of the 900 keV Li particle beam in the boron 10 is 2 μm. For this reason, the height (thickness) of the converter layer 212 is preferably about 2 to 4 μm. The upper surface of the converter layer 212 and the upper surface of the shielding metal 210 may exist on the same plane. The distance between the shielding metal 110 and the P (N) type substrate 102 is preferably about 1 μm.

  The radiation detection apparatus 200 has the same configuration as that of the radiation detection apparatus 100 shown in FIG.

(Operation example)
An operation of neutron detection in the radiation detection apparatus 200 will be described. When neutrons are incident from the converter layer 212 side of the radiation detection apparatus 200, the neutrons react with the boron 10 of the converter layer 212 ( ¹³ (n, α) ⁷ Li reaction), and are converted into α rays and Li particle beams. Is done. One of the α ray and the Li particle beam is emitted to the detection unit 2220 side. The charged particle beam emitted to the detection unit 220 side is detected by the detection unit 220. A part of the charged particle beam emitted to the detection unit 220 side hits the shielding metal 210. When charged particles are incident on the detection unit 220, the charged particles generate electron-hole pairs in a depletion layer near the PN junction of the detector 220. The detection unit 220 detects a charged particle (α ray or Li particle beam) by detecting a current due to the electron-hole pair. Further, when charged particles hit the shielding metal 210, the detection unit 220 does not detect them. This is because the charged particles are attenuated by the shielding metal 210 and do not reach the detection unit 220. Since the radiation detection apparatus 200 does not include the silicon oxide film 108 as in the first embodiment, the charged particles are not attenuated by the silicon oxide film in the radiation detection apparatus 200.

  Moreover, the radiation detection apparatus 200 can determine the position where the neutron is incident with the position resolution of the installation interval of the detection unit 220, as in the radiation detection apparatus 100 of the first embodiment.

(Effect of Embodiment 2)
The converter layer 212 of the radiation detection apparatus 200 converts incident neutrons into charged particles such as α rays and Li particle rays when they react with the boron 10. The charged particles are not attenuated by the silicon oxide film unlike the radiation detection apparatus 100 of the first embodiment. Therefore, the radiation detection apparatus 200 can detect the incidence of neutrons more efficiently than the radiation detection apparatus 100.

[Embodiment 3]
Next, Embodiment 3 will be described. The third embodiment has common points with the first and second embodiments. Accordingly, here, mainly the differences will be described, and description of common points will be omitted. In the third embodiment, the same configuration as that of the radiation detection apparatus 100 or the radiation detection apparatus 200 is stacked. Although the radiation detection apparatus of Embodiment 1 and Embodiment 2 was an apparatus that mainly detects thermal neutrons, the radiation detection apparatus 300 of the present embodiment detects fast neutrons.

(Configuration example)
FIG. 9 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the present embodiment. The radiation detection apparatus 300 includes a P (N) type substrate 302, a detection unit 320, a metal (shielding metal) 310, and a converter layer 312. The P (N) type substrate 302, the detection unit 320, and the metal (shielding metal) 310 are the same as the P (N) type substrate 202, the detection unit 220, and the shielding metal 210 of the second embodiment, respectively. In the radiation detection apparatus 300, a plurality of layers including a P (N) type substrate 302, a detection unit 320, a metal (shielding metal) 310, and a converter layer 312 are stacked. In the example of FIG. 9, each layer is a first layer, a second layer, and a third layer from the upper layer. In the example of FIG. 9, there are three layers, but two layers or more are sufficient, and the number is not limited to three layers. Moreover, the layer laminated | stacked by the radiation detection apparatus 300 may be the same layer as the radiation detection apparatus 100 of Embodiment 1. The layers other than the uppermost layer may not include the metal (shielding metal) 310 and the converter layer 312. The layers are in close contact.

The converter layer 312 includes a substance containing a large amount of hydrogen, such as paraffin and polyethylene. The converter layer 312 may be only a substance containing a large amount of hydrogen. Neutrons (fast neutrons) incident on the converter layer 312 collide with hydrogen nuclei (H ⁺ ) with a predetermined probability, and blow off the hydrogen nuclei. The repelled hydrogen nucleus has high energy and can pass through the shielding metal 310. Therefore, the shielding metal 310 may not exist. That is, a silicon oxide film may be used instead of the shielding metal 310. Further, when the radiation detection apparatus 300 includes the same layer as that of the radiation detection apparatus 200 of the second embodiment, a converter layer without a shielding metal may be in contact with the detection unit 320. The material and height (thickness) of the converter layer 312 can be set to 50 μm with polyethylene, for example. If the converter layer 312 is too thick, the position resolution decreases, and if it is too thin, the proportion of neutrons that blow off the hydrogen nuclei decreases.

  The detection unit 320 detects hydrogen nuclei (charged particles) by a depletion layer formed in the detection unit 320 at the time of reverse bias of the low-capacity PN junction. Hydrogen nuclei generate electron-hole pairs in the depletion layer near the PN junction. The detection unit 320 detects a hydrogen nucleus by detecting a current due to the electron-hole pair. When detected by a plurality of layers of detection units 320, the incident direction of hydrogen nuclei can be determined by connecting the detected positions of the detectors 320 in a straight line. The installation interval of the detection unit 320 is the position resolution of the radiation detection apparatus 300. However, when the converter layer 312 is thick, the position resolution of the radiation detection apparatus 300 also depends on the thickness (D) of the converter layer 312. Here, it is assumed that the angle θ is an angle formed by the normal direction of the radiation incident surface (the upper surface of the converter layer 312) of the radiation detection apparatus 300 and the incident direction of the hydrogen nuclei (see FIG. 9). When the thickness of the converter layer 312 is sufficiently larger than the installation interval of the detectors 320, the position resolution of the radiation detection apparatus 300 is Dtanθ if only proton beams with an angle θ or less are used.

(Operation example)
An operation of neutron detection in the radiation detection apparatus 300 will be described. When neutrons are incident from the converter layer 312 side of the radiation detection apparatus 300, neutrons (fast neutrons) blow off hydrogen nuclei with a predetermined probability. A hydrogen nucleus (proton beam) is a charged particle. Hydrogen nuclei are detected by the detection unit 320. A reverse bias is applied to the detection unit 320, and a depletion layer is formed in the vicinity of the PN junction. When hydrogen nuclei are incident on the detector 320, the charged particles are
Electron hole pairs are generated in the depletion layer near the PN junction of the detector 320. The detection unit 320 detects a hydrogen nucleus (proton beam) by detecting a current due to the electron-hole pair. The hydrogen nuclei bounced off by fast neutrons have large energy and can be detected by the detection unit 320 in another layer (lower layer). In many cases, hydrogen nuclei (proton beams) that have been blown off by fast neutrons are detected by a plurality of layers of detection units 320. The trajectory of the proton line is almost straight.

  When a proton beam is detected by the detection units 320 of a plurality of layers, the detection unit 320 in which the proton beam is detected is connected in a straight line, and the layer of the uppermost layer among the layers in which the detection unit 320 in which the proton beam is detected exists. The position where the converter layer and the straight line intersect is the position where the neutron is incident. The position where the neutron is incident is the position where the neutron flew off the hydrogen nucleus. When the position of the detection unit 320 that has detected the proton beam is not in a straight line, the radiation detection apparatus 300 uses the coordinates (three-dimensional coordinates) of the position of the detection unit 320 that has detected the proton beam by the least square method or the like. A straight line can be obtained. Therefore, as the number of layers increases, the number of detection units 320 that detect proton beams increases, and the trajectory of proton beams can be obtained more accurately. In order to accurately obtain the trajectory of the proton beam, it is required to accurately arrange the position of the detection unit 320 of each layer and the position of each layer. This is because if the error in the position of the detector 320 is large, the error in the trajectory of the proton beam becomes large.

  In addition, a proton beam is incident on the surface of the first layer from the direction of the normal of the surface of the first layer, and the detection unit 320 of a plurality of layers detects carriers, thereby detecting the position of the detection unit 320. Can be calibrated. That is, it is determined that the detection unit 320 that has detected the carrier exists in the normal direction of the surface of the first layer. Assuming that the detection unit 320 of each layer is accurately located in each layer and the distance between each layer is known, a proton beam is incident from at least two locations on the surface of the first layer, and a plurality of layers By detecting the carrier by the detection unit 320, the positions of all the detection units 320 can be calibrated. When the incident position of the proton beam can be controlled with higher accuracy than the interval between the detection units 320 in each layer, the position of the detection unit 320 can be calibrated with higher accuracy than the interval between the detection units 320 in each layer. That is, the position of the detection unit 320 is determined with higher accuracy than the interval between the detection units 320. By accurately obtaining the position of the detection unit 320, the trajectory of the proton beam can be obtained more accurately.

(Effect of Embodiment 3)
The radiation detection apparatus 300 includes a plurality of layers. Each layer includes a silicon substrate 302, a detection unit 320, a metal (shielding metal) 310, and a converter layer 312. Each layer may not include the shielding metal and the silicon oxide film 308. Layers other than the top layer may not include the converter layer 312. Converter layer 312 includes a substance containing a large amount of hydrogen.

  In the converter layer 312 of the radiation detection apparatus 300, incident neutrons (fast neutrons) blow off the hydrogen nuclei. The repelled hydrogen nucleus (proton beam) is incident on the detection unit 320. The proton beam is a depletion layer near the PN junction of the detection unit 320 and generates electron-hole pairs. The detection unit 320 detects a proton beam by detecting a current due to the electron-hole pair. Since the proton beam has high energy, it is also detected by the lower detection unit 320. The position at which the straight line connecting the plurality of detection units 120 that detect proton beams and the converter layer 312 of the uppermost detection unit 320 among the detection units 320 intersect is the position where the neutrons repelled the hydrogen nuclei. is there. That is, the radiation detection apparatus 300 can determine that neutrons have entered this position.

  When the installation interval of the detection unit 320 is sufficiently small with respect to the thickness of the converter layer, the position resolution of the radiation detection apparatus 300 is the installation interval of the detection unit 320. When the thickness of the converter layer 312 is sufficiently larger than the installation interval of the detectors 320, the position resolution of the radiation detection apparatus 300 is Dtanθ if only proton beams with an angle θ or less are used.

  When gamma rays are incident on the radiation detection apparatus 300, only one detection unit 320 generates a signal. On the other hand, the proton beam is detected by a plurality of detection units 320. Therefore, the radiation detection apparatus 300 can separate gamma rays and proton rays.

[Embodiment 4]
Next, a fourth embodiment will be described. The fourth embodiment has common points with the first embodiment, the second embodiment, and the third embodiment. Accordingly, here, mainly the differences will be described, and description of common points will be omitted. In the fourth embodiment, similar to the third embodiment, the same configuration as that of the radiation detection apparatus 100 or the radiation detection apparatus 200 is stacked. The radiation detection apparatus 400 according to the fourth embodiment detects thermal neutrons and fast neutrons.

(Configuration example)
FIG. 10 is a diagram illustrating an example of a cross section of the radiation detection apparatus according to the present embodiment. The radiation detection apparatus 400 includes a P (N) type substrate 402, a detection unit 420, a metal (shielding metal) 410, and a first converter layer 412. These are the same as the P (N) type substrate 202, the detection unit 220, the shielding metal 210, and the converter layer 212 of the second embodiment, respectively. The radiation detection apparatus 400 further includes a second converter layer 414. The second converter layer 414 is the same as the converter layer 312 of the third embodiment. In the radiation detection apparatus 400, a plurality of layers including a P (N) type substrate 402, a detection unit 420, a metal (shielding metal) 410, a first converter layer 412, and a second converter layer 414 are stacked. In the example of FIG. 10, each layer is a first layer, a second layer, and a third layer from the upper layer. In the example of FIG. 10, there are three layers, but two layers or more are sufficient, and the number is not limited to three layers. Moreover, the layer laminated | stacked by the radiation detection apparatus 400 may be a layer containing the silicon oxide film similar to the radiation detection apparatus 100 of Embodiment 2. FIG. The layers other than the uppermost layer may not include the metal (shielding metal) 410, the first converter layer 412, and the second converter 414. The layers are in close contact. The position of the first converter layer 412 and the position of the second converter layer 414 may be interchanged.

  The first converter layer 412 is a layer similar to the converter layer 112 of the first embodiment or the converter layer 212 of the second embodiment. The second converter layer 414 is a layer similar to the converter layer 312 of the third embodiment. That is, thermal neutrons react with boron 10 in the first converter layer, and fast neutrons blow off hydrogen nuclei in the second converter layer.

  FIG. 11 is a diagram illustrating an example of sensitivity of the first converter layer and the second converter layer. In the example of FIG. 11, the first converter layer 412 is boron 10 and has a thickness of 5 μm, and the second converter layer 414 is polyethylene and has a thickness of 50 μm. The graph of FIG. 11 is a graph which shows the sensitivity of each converter layer with respect to the energy of neutrons. In the example of FIG. 11, the first converter layer 412 is more sensitive to low energy neutrons, and the second converter layer 414 is more sensitive to high energy neutrons. The sensitivity of the radiation detection apparatus 400 to the energy of neutron is the sum of these graphs.

(Operation example)
An operation of neutron detection in the radiation detection apparatus 400 will be described. When thermal neutrons are incident from the first converter layer 414 side of the first layer of the radiation detection device 400, the thermal neutrons react with the boron 10 of the first converter layer 412 ( ¹³ (n, α) ⁷ Li reaction). And converted into α rays and Li particle rays. This operation is the same as the operation of the radiation detection apparatus 100 of the first embodiment. Further, when fast neutrons are incident from the second converter layer 414 side of the first layer of the radiation detection apparatus 400, the fast neutrons blow off the hydrogen nuclei of the second converter layer 414 with a predetermined probability. This operation is the same as the operation of the radiation detection apparatus 300 of the third embodiment.

When the detection unit 420 detects a signal, the radiation detection apparatus 400 determines that the thermal neutron is incident as in the first embodiment, assuming that thermal neutron is incident. That is, the radiation detection apparatus 400 determines that thermal neutrons are incident on the first converter layer 412 almost directly above the detection unit 420 that has detected the signal.

  Moreover, the radiation detection apparatus 400 calculates | requires the position where the fast neutron was injected like Embodiment 3, when the signal was detected by the some detection part 420, assuming that the fast neutron was injected. That is, the radiation detection apparatus 400 connects the detection unit 420 that has detected the signal in a straight line, and the second converter layer 414 in the uppermost layer among the layers in which the detection unit 420 that has detected the signal exists intersects the straight line. The position where the neutron is incident is determined as the position where the neutron is incident.

  Therefore, the radiation detection apparatus 400 can detect the positions where neutrons are incident from low energy neutrons to high energy neutrons.

(Effect of Embodiment 4)
The radiation detection apparatus 400 has two types of converter layers. The radiation detection apparatus 400 has sensitivity to a wide energy width of neutrons by having two types of converter layers. In addition, the radiation detection apparatus 400 can accurately detect the position where the neutron is incident by disposing the detection unit 420 in three dimensions.

100 Radiation detector
102 P (N) type substrate
108 Silicon oxide film (SiO ₂ )
110 metal (shield metal)
112 Converter layer
120 detector
121 N (P) type semiconductor
122 N (P) type semiconductor
123 Silicon oxide film (SiO ₂ )
124 Polysilicon
131 Wiring
132 Wiring
133 Wiring
141 transistor
142 transistor
151 Longitudinal switch
152 Horizontal switch
160 Amplifier
171 transistor
172 transistor
181 Longitudinal switch
182 Horizontal switch
200 Radiation detector
202 P (N) type substrate
206 Device isolation membrane
210 Metal (shield metal)
212 Converter layer
220 detector
300 Radiation detector
302 P (N) type substrate
306 Element isolation film
310 Metal (shield metal)
312 Converter layer
320 detector
400 Radiation detector
402 P (N) type substrate
410 Metal (shield metal)
412 First converter layer
414 Second converter layer
420 Detection unit

Claims (2)

A converter that reacts with neutrons to generate charged particles;
A plurality of detection circuits for detecting the charged particles formed on the semiconductor substrate;
A shielding unit for restricting the arrival direction of the charged particles incident on each of the detection circuits;
A radiation detection apparatus comprising: The radiation detection apparatus according to claim 1, wherein the detection circuit includes a PN junction.

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